java - 如何让JComboBox自动更新？

Question

我正在努力更新 JComboBox 中的项目。当我从文件加载项目时，组合框显示正确，但是当我尝试从组合框项目添加或删除项目时，组合框不会自动更新，它仍然保留相同的项目。这是我的代码这是我加载组合框项目的位置

ObjectInputStream input;
    try {
        // TODO add your handling code here:           
        JFileChooser openFileChooser = new JFileChooser();            
        openFileChooser.setCurrentDirectory(new File("."));
        if (openFileChooser.showOpenDialog(null) == JFileChooser.APPROVE_OPTION){
            input = new ObjectInputStream(new FileInputStream(openFileChooser.getSelectedFile()));
            diary = (Diary)input.readObject();
            jTextArea3.setText(diary.getUnitCollection().toString());
            input.close();
            //Load Unit Item
            for (Unit u: diary.getUnitCollection()){
                jComboBox8.addItem(u.getUnitName());
                jComboBox1.addItem(u.getUnitName());
            }
        }            
    } catch (ClassNotFoundException ex) {
        Logger.getLogger(GUI.class.getName()).log(Level.SEVERE, null, ex);
    } catch (IOException ex) {
        Logger.getLogger(GUI.class.getName()).log(Level.SEVERE, null, ex);
    }

这是删除项目的按钮

 private void jButton7ActionPerformed(java.awt.event.ActionEvent evt) {                                         
    // TODO add your handling code here:
    for (int i = 0; i < diary.getUnitCollection().size(); i++){
            if (jComboBox8.getSelectedItem().equals(diary.getUnitCollection().get(i).getUnitName())){
                diary.getUnitCollection().remove(diary.getUnitCollection().get(i));
                jTextArea3.setText("The Unit " + jComboBox8.getSelectedItem()+ " has been removed successfully");                   
            }
        }
}             

编辑:只需修复样式(代码块)

Answer 1

您需要通过模型添加和删除内容，请查看http://docs.oracle.com/javase/7/docs/api/javax/swing/DefaultComboBoxModel.html